Have a 2008 E320cdi, get 45+ mpg on motorway 42/3 mpg cross country and 30/32 around town, bit lower in winter. Great engine , very smooth, love the power for overtaking Only problem has been small oil leak from turbo ( I think that is what the garage said ) pools at top of engine, sorted by new seal, not expensive. Not had a problem with swirl flap motors unlike other reports, but this is not a major expense to fix if it happens. Servicing at dealers not too expensive, switched to MB Indi last time A service cost £250. Only unexpected repair was broken front coil Spring , quite common on many models these days with all the speed humps. I missed one at 35 mph and Spring failed 300 MPs later. IMO the 320 is the one to go for, even if older, was not over impressed with a more modern 220 that I drove.